[PATCH v3 08/28] efi/libstub: Drop .discard.addressable from the stub objects

[Josh Poimboeuf <jpoimboe@kernel.org>]

On arm64, riscv and loongarch, the EFI stub objects are objcopy'd with
--prefix-alloc-sections=.init, which renames every allocatable section.

The .discard.addressable section is allocatable, so if
STACK_FRAME_NON_STANDARD() and __ADDRESSABLE() are used, the section
gets renamed and never discarded:

  ld: warning: orphan section `.init.discard.addressable' from `vmlinux.o' being placed in section `.init.discard.addressable'

The section is also a problem for the stub's absolute relocation check
on some arches.

In preparation for using STACK_FRAME_NON_STANDARD() in libstub code,
remove the section for both cases.

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
---
 drivers/firmware/efi/libstub/Makefile | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 77a2b2d74f3f6..0d5d99c3cacdd 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -155,6 +155,11 @@ STUBCOPY_FLAGS-$(CONFIG_LOONGARCH)	+= --prefix-alloc-sections=.init \
 					   --prefix-symbols=__efistub_
 STUBCOPY_RELOC-$(CONFIG_LOONGARCH)	:= R_LARCH_MARK_LA
 
+# Drop the section created by __ADDRESSABLE() from the absolute symbol check
+# and the objcopy, otherwise it gets prefixed and doesn't get discared.
+STUBCOPY_RM_SECTIONS			:= --remove-section=.discard.addressable
+STUBCOPY_FLAGS-y			+= $(STUBCOPY_RM_SECTIONS)
+
 $(obj)/%.stub.o: $(obj)/%.o FORCE
 	$(call if_changed,stubcopy)
 
@@ -166,7 +171,7 @@ $(obj)/%.stub.o: $(obj)/%.o FORCE
 #
 quiet_cmd_stubcopy = STUBCPY $@
       cmd_stubcopy =							\
-	$(STRIP) --strip-debug -o $@ $<;				\
+	$(STRIP) --strip-debug $(STUBCOPY_RM_SECTIONS) -o $@ $<;	\
 	if $(OBJDUMP) -r $@ | grep $(STUBCOPY_RELOC-y); then		\
 		echo "$@: absolute symbol references not allowed in the EFI stub" >&2; \
 		/bin/false;						\
-- 
2.55.0